1. Field of the Invention
The present invention relates to a process for preparation of a cellulose solution for the spinning of fibres, filaments or films therefrom.
2. Description of the Related Art
The process to dissolve cellulose in tertiary amine oxide was disclosed in 1939 by Graenacher et al in U.S. Pat. No. 2,179,181. In accordance with the disclosure, the N-Oxide of trialkylamine or alkyl cycloaliphatic tertiary amine having 14 carbon atoms or less are suitable for cellulose solvent. The drawback of the process is that the solution has low cellulose content and high viscosity.
Another process to dissolve cellulose and other similar compound in tertiary amine-oxide is disclosed in U.S. Pat. No. 3,447,956 & U.S. Pat. No. 3,447,939 by Johnson et al in 1969, where a cyclic mono (N-methyl amine-N-Oxide) compound such as N-Methyl Morpholine-N-Oxide (NMMO), N-Methyl Pyro lidine N-Oxide etc. are used as solvent. This method is used to strengthen the paper or fabric strength.
In another disclosure by C. C. Mc Corsley III et al, in U.S. Pat. No. 4,142,913, a process is provided to make a solid precursor of a solution of cellulose in tertiary amine oxide. The product may be comminuted to form chips which are further fed into an extruder for shaping it into a celluosic article. The main disadvantage of this process is that the solid precursor of Cellulose & Amine oxide is highly hygroscopic and if too much water is absorbed, the phases separate. Another serious disadvantage associated with this process is that the remelting of chips for extrusion causes a severe degradation of cellulose and the remelted mass does not have proper spinning properties.
It is generally known that cellulose can be activated either by high energy radiation treatment (such as electron beam) or hydrothermal treatment or by chemical treatments. All these treatments need additional investment and also depolymerization of cellulose takes place.
An object of this invention is to propose an improved process for preparation of a cellulose solution for spinning of fibres, filaments or films therefrom.
Another object of the present invention is to provide a suitable method to dissolve cellulose in the tertiary amine oxide solution, which can directly be fed into extruder without associated the aforesaid problem.
Another objection of the invention is to provide a process which can make a cellulose-amine thermoplastic polymer having high percentage of cellulose from 7% to 28% and preferably 12%-22%.
Therefore, still another object of the present invention is to provide a simple and effective dissolution system by activating cellulose before it is dissolved in amine oxide solution.
A more specific object of the invention is to provide a process to prepare cellulose solution in amine oxide solvent which has higher cellulose content by adopting the online activation system.
A further object of the invention is to provide an improved process for making spinnable solution of cellulose and amine oxide having higher cellulose concentration and better uniformity than those described in prior arts.
A still further object of the invention is to provide a process to make a mesomorphous solution of cellulose having liquid crystal in the solution itself.
Another object of the invention is to provide a process for making cellulosic articles from cellulose amine-oxide solution which does not pollute the environment with waste product/metal ions/sulphur compounds etc. as in case of viscose process.
Yet another object of this invention is to provide a simple and online method to activate the cellulose to increase its swelling and dissolution power in aqueous amine oxide solution.